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| Registros recuperados: 59 | |
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| Lens, F.; Baas, P.; Jansen, S.; Smets, E.. |
| The wood structure of 71 species representing 24 genera of the pantropical Lecythidaceae s.l., including the edible Brazil nuts (Bertholletia excelsa) and the spectacular cannon-ball tree (Couroupita guianensis), was investigated using light and scanning electron microscopy. This study focused on finding phylogenetically informative characters to help elucidate any obscure evolutionary patterns within the family. The earliest diverging subfamily Napoleonaeoideae has mixed simple/scalariform vessel perforations, scalariform vessel-ray pitting, and high multiseriate rays, all features that are also present in Scytopetaloideae. The wood structure of Napoleonaea is distinct, but its supposed close relative Crateranthus strongly resembles Scytopetaloideae. The... |
| Tipo: Article / Letter to the editor |
Palavras-chave: Ericales; Lecythidaceae s.l.; Lecythidaceae s.s.; Napoleonaeaceae; Scytopetalaceae; Systematic wood anatomy; 42.48. |
| Ano: 2007 |
URL: http://www.repository.naturalis.nl/record/422216 |
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| Lens, F.; Smets, E.; Jansen, S.. |
| The wood anatomical structure of 11 out of 13 genera from four tribes of the Vaccinioideae, namely Andromedeae s.s., Gaultherieae, Lyonieae and Oxydendreae (Ericaceae s.l.), is described using light and scanning electron microscopy. Several features of the secondary xylem support the tribal classification based on molecular data: arrangement of vessel-ray pitting, height of multiseriate rays and the shape of the body ray cells. Oxydendreae are clearly defined from the other representatives by various wood anatomical features. Gaultherieae can be distinguished from Lyonieae by differences in vessel perforation plates, vessel-ray pitting, height and structure of multiseriate rays, and occurrence of prismatic crystals, but the wood of Andromedeae s.s. is... |
| Tipo: Article / Letter to the editor |
Palavras-chave: Comparative wood anatomy; Andromedeae; Gaultherieae; Lyonieae; Oxydendreae; Vaccinioideae; Ericaceae; Andromedeae sensu Stevens; Pith structure; 42.58. |
| Ano: 2004 |
URL: http://www.repository.naturalis.nl/record/424620 |
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| Schols, P.; Wilkin, P.; Furness, C.; Huysmans, S.; Smets, E.. |
| Pollen character evolution in yams (Dioscorea: Dioscoreaceae) was investigated in relation to the phylogeny obtained from a recent combined analysis of rbcL and matK gene sequences. The following characters were evaluated: pollen size, aperture number, sexine ornamentation, perforation density, and orbicule presence or absence. Continuous characters were coded using the gap weighting method. Each character was optimized using MacClade onto a tree selected at random from analyses based on molecular data of Wilkin et al. The results indicate that in Dioscorea pollen size decreases in the more derived clades. The latter observation may be related to the evolution of annually replaced tubers. Aperture number increases from one in the monosulcate Stenophora... |
| Tipo: Article / Letter to the editor |
Palavras-chave: Dioscorea; Dioscoreaceae; Pollen; Evolution; Phylogeny. |
| Ano: 2005 |
URL: http://www.repository.naturalis.nl/record/407309 |
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| Lens, F.; Endress, M.E.; Baas, P.; Jansen, S.; Smets, E.; , D.. |
| This study contributes to our understanding of the phylogenetic signifi cance and major evolutionary trends in the wood of the dogbane family (Apocynaceae), one of the largest and economically most important angiosperm families. Based on LM and SEM observations of 56 Apocynoideae species — representing all currently recognized tribes — and eight Periplocoideae, we found striking differences in vessel grouping patterns (radial multiples vs. large clusters) between the mainly nonclimbing apocynoid tribes (Wrightieae, Malouetieae, Nerieae) and the climbing lineages (remaining Apocynoideae and Periplocoideae). The presence of large vessel clusters in combination with fibers in the ground tissue characterizing the climbing Apocynoideae and Periplocoideae... |
| Tipo: Article / Letter to the editor |
Palavras-chave: Apocynaceae; Apocynoideae; APSA clade; Climbing vs. nonclimbing anatomy; Periplocoideae; Systematic wood anatomy; Tribal classification; 42.58. |
| Ano: 2009 |
URL: http://www.repository.naturalis.nl/record/424670 |
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| Dessein, S.; Ochoterena, H.; De Block, P.; Lens, F.; Robbrecht, E.; Schols, P.; Smets, E.; Vinckier, S.; Huysmans, S.. |
| In the 1990s Rubiaceae became a hot spot for systematists, mainly due to the comprehensive treatment of the family by Robbrecht in 1988. Next to the exploration of macromolecular characters to infer the phylogeny, the palynology of Rubiaceae finally received the attention it deserves. This article aims to present a state-of-the-art analysis of the systematic palynology of the family. The range of variation in pollen morphology is wide, and some of the pollen features are not known from other angiosperm taxa; e.g., a looplike or spiral pattern for the position of apertures in pantoaperturate grains. We compiled an online database at the generic level for the major pollen characters and orbicule presence in Rubiaceae. An overview of the variation is... |
| Tipo: Article / Letter to the editor |
Palavras-chave: Rubiaceae; Pollen morphology; Palynology; Phylogeny. |
| Ano: 2005 |
URL: http://www.repository.naturalis.nl/record/407298 |
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| Vrijdaghs, A.; Goetghebeur, P.; Smets, E.; Muasya, A.. |
| Background and Aims In 1976 the monotypic genus Hellmuthia was placed in the Hypolytreae s.l., but was subsequently ascribed to the Mapanioideae, tribe Chrysitricheae, mainly because of the presence in Hellmuthia of two lateral, mapanioid-like floral scales with ciliated keels, the anatomy of the nutlet, the embryo and the inflorescence. Recently, based on cladistic analyses and supported by pollen ontogenetic evidence, Hellmuthia was transferred to a Cyperaceae, tribe Cypereae, clade mainly consisting of Ficinia and Isolepis. In this study, the floral ontogeny in Hellmuthia was investigated and compared with the floral ontogeny in Paramapania, with special attention for the floral scales. Methods Freshly collected inflorescences of Hellmuthia... |
| Tipo: Article / Letter to the editor |
Palavras-chave: Floral scales; Paramapania; Floral ontogeny; Cyperaceae; Hellmuthia; SEM; Homology. |
| Ano: 2006 |
URL: http://www.repository.naturalis.nl/record/407327 |
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| Groeninckx, I.; Vrijdaghs, A.; Huysmans, S.; Smets, E.; Dessein, S.. |
| Background and Aims Members of Rubiaceae are generally characterized by an inferior ovary. However, Mitrasacmopsis is cited in the literature as having a semi-inferior to superior ovary. It has previously been hypothesized that the gynoecial development of Rubiaceae with semi-inferior to superior ovaries takes place in the same way as in Gaertnera, one of the most commonly cited rubiaceous genera with a superior ovary. To test this hypothesis, a floral ontogenetic study of Mitrasacmopsis was carried out with special attention paid to the gynoecial development. Methods Floral ontogeny and anatomy of Mitrasacmopsis were examined using scanning electron and light microscopy. Key Results At an early developmental stage, a concavity becomes visible in the... |
| Tipo: Article / Letter to the editor |
Palavras-chave: Mitrasacmopsis quadrivalvis; Gaertnera; Floral ontogeny; 42.48. |
| Ano: 2007 |
URL: http://www.repository.naturalis.nl/record/422222 |
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| Lens, F.; Dressler, S.; Jansen, S.; Van Evelghem, L.; Smets, E.. |
| Wood samples of 49 specimens representing 31 species and 11 genera of woody balsaminoids, i.e., Balsaminaceae, Marcgraviaceae, Pellicieraceae, and Tetrameristaceae, were investigated using light microscopy and scanning electron microscopy. The wood structure of Marcgraviaceae, Pellicieraceae, and Tetrameristaceae is characterized by radial vessel multiples with simple perforation plates, alternate vessel pitting, apotracheal and paratracheal parenchyma, septate libriform fibers, and the presence of raphides in ray cells. Tetrameristaceae and Pellicieraceae are found to be closely related based on the occurrence of unilaterally compound vessel-ray pitting and multiseriate rays with long uniseriate ends. The narrow rays in Pelliciera are characteristic of... |
| Tipo: Article / Letter to the editor |
Palavras-chave: Balsaminaceae; Balsaminoid clade; Ericales; Marcgraviaceae; Paedomorphism; Pellicieraceae; Tetrameristaceae; Wood anatomy; 42.40. |
| Ano: 2005 |
URL: http://www.repository.naturalis.nl/record/407273 |
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| Rabaey, D.; Lens, F.; Smets, E.; Janssen, S.. |
| Background and Aims Intervascular pit membranes were examined within Ericales to determine the distribution and structure of torus-like thickenings. Methods Forty-nine species representing 12 families of the order Ericales were investigated using light, scanning and transmission electron microscopy. They were compared with four species of Oleaceae to determine the true nature of the thickenings. Key Results Pit membranes with torus-like thickenings were observed in seven species of Ericaceae and were found to be amorphous, plasmodesmata-associated structures with an irregular distribution. These pseudo-tori show major differences compared with true tori with respect to their distribution and ultrastructure. Genuine tori, which are strongly correlated... |
| Tipo: Article / Letter to the editor |
Palavras-chave: Ericaceae; Ericales; Oleaceae; Pit membrane; Plasmodesmata; Pseudo-torus; Torus; Tracheary elements. |
| Ano: 2006 |
URL: http://www.repository.naturalis.nl/record/407321 |
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| Lens, F.; Luteyn, J.L.; Smets, E.; Jansen, S.. |
| The ecological wood anatomy of 128 vaccinioid wood samples (including 115 species, 35 genera), collected between 39°S and 60°N latitude and 10 m to 3400 m altitude is studied. Several wood anatomical features within the subfamily, viz. tangential vessel diameter, average length of tracheary elements, height of multiseriate rays, and presence of prismatic crystals are negatively correlated with increasing latitude, while vessel density and helical thickenings show a positive correlation with increasing latitude. Similar latitudinal trends are found within the genus Vaccinium (31 species studied). The correlation between various wood anatomical features and latitude is surprisingly high despite the fact that most tropical species grow in montane regions,... |
| Tipo: Article / Letter to the editor |
Palavras-chave: Altitude; Ecological and functional wood anatomy; Ericaceae; Latitude; Vaccinioideae; Vaccinium; 42.58. |
| Ano: 2004 |
URL: http://www.repository.naturalis.nl/record/424624 |
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| Schols, P.; Furness, C.; Merckx, V.; Wilkin, P.; Smets, E.. |
| Pollen and orbicule ontogeny in representatives of three genera of Dioscoreales—Narthecium ossifragum Huds. (Nartheciaceae), Tacca artocarpifolia Seem. and Tacca chantrieri Andre´ (Dioscoreaceae), and Dioscorea communis (L.) Caddick & Wilkin (Dioscoreaceae)—is described and illustrated using LM, SEM, and TEM. The main difference is in microsporogenesis, which is successive in Narthecium Huds. and simultaneous in Tacca J.R. & G. Forst. and Dioscorea L. This is reflected in the tetrad configuration but not in the apertures: Narthecium and Tacca are monosulcate, while Dioscorea has two equatorial apertures. Other features of pollen development are similar in all three genera. Exine development starts at the proximal pole, and during the tetrad stage,... |
| Tipo: Article / Letter to the editor |
Palavras-chave: Intine; Microsporogenesis; Monocotyledons; Orbicules; Pollen ontogeny; Systematics; Tapetum; Tetrads. |
| Ano: 2005 |
URL: http://www.repository.naturalis.nl/record/407299 |
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| Vinckier, S.; Cadot, P.; Smets, E.. |
| In the anthers of flowering plants, gymnosperms, and seed ferns, tiny (¡1 mm) granules might occur on the radial and innermost tangential wall of secretory tapetum cells. These sporopollenin granules develop simultaneously with the pollen exine and are called orbicules or Ubisch bodies. The present paper focuses on two quite different topics associated with orbicules. The morphological and ultrastructural diversity of orbicules in the order Gentianales is summarized, and it is demonstrated that orbicules are a plesiomorphic feature in the order. Furthermore, orbicule characters seemed to be correlated with evolutionary trends in pollen dispersal unit and tapetum type features. In the second part, we report on our investigation of Corylus avellana L.... |
| Tipo: Article / Letter to the editor |
Palavras-chave: Orbicules; Morphology; Diversity; Gentianales; Plesiomorphic feature; Pollen; Corylus avellana L.. |
| Ano: 2005 |
URL: http://www.repository.naturalis.nl/record/407306 |
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| Registros recuperados: 59 | |
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